/*
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 *
 * This file is a derivative of code released under the terms listed below.
 *
 */
/*
*  Copyright (c) 2013,
*      Tobias Blaschke <code@tobiasblaschke.de>
*  All rights reserved.

*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions are met:
*
*  1. Redistributions of source code must retain the above copyright notice,
*     this list of conditions and the following disclaimer.
*
*  2. Redistributions in binary form must reproduce the above copyright notice,
*     this list of conditions and the following disclaimer in the documentation
*     and/or other materials provided with the distribution.
*
*  3. The names of the contributors may not be used to endorse or promote
*     products derived from this software without specific prior written
*     permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
*  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
*  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
*  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
*  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
*  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
*  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
*  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*/
package com.ibm.wala.dalvik.util;

import com.ibm.wala.dalvik.ipa.callgraph.androidModel.parameters.IInstantiationBehavior;
import com.ibm.wala.dalvik.ipa.callgraph.impl.AndroidEntryPoint;
import com.ibm.wala.ipa.cha.IClassHierarchy;
import com.ibm.wala.types.Selector;
import com.ibm.wala.types.TypeName;
import com.ibm.wala.types.TypeReference;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;

/**
 * Does optional checks before building the CallGraph.
 *
 * <p>The android-model expects some configuration to be of specific settings to unfold it's full
 * performance.
 *
 * <p>These checks may be run before building the CallGraph to verify everything is in place.
 *
 * @author Tobias Blaschke &lt;code@tobiasblaschke.de&gt;
 * @since 2013-11-01
 */
public class AndroidPreFlightChecks {
  private final AndroidEntryPointManager manager;
  //    private final AnalysisOptions options;
  private final IClassHierarchy cha;

  public AndroidPreFlightChecks(AndroidEntryPointManager manager, IClassHierarchy cha) {
    this.manager = manager;
    //        this.options = options;
    this.cha = cha;
  }

  public enum Test {
    OVERRIDES,
    INTENTS,
    REUSE,
    STUBS_VERSION,
    OBJECT_IN_EP
  }

  /**
   * Perform all checks defined in this class.
   *
   * @return if the checks passed
   */
  public boolean all() {
    return allBut(EnumSet.noneOf(Test.class));
  }

  /**
   * Perform all checks defined in this class but the listed ones.
   *
   * @param skip checks not to perform
   * @return if the checks passed
   */
  public boolean allBut(Set<Test> skip) {
    boolean pass = true;

    if (!skip.contains(Test.OVERRIDES)) {
      pass &= checkOverridesInPlace();
    }
    if (!skip.contains(Test.INTENTS)) {
      pass &= checkIntentSpecs();
    }
    if (!skip.contains(Test.REUSE)) {
      pass &= checkAllComponentsReuse();
    }
    if (!skip.contains(Test.STUBS_VERSION)) {
      pass &= checkStubsVersion();
    }
    if (!skip.contains(Test.OBJECT_IN_EP)) {
      pass &= checkNoObjectInEntryPoints();
    }
    return pass;
  }

  /**
   * The Overrides are needed to resolve intents in the startComponent-Calls.
   *
   * <p>Without these overrides the startComponent-Calls will not be overridden. In a static
   * analysis there won't be a way to resolve the actual target of the call.
   *
   * @see com.ibm.wala.dalvik.ipa.callgraph.propagation.cfa.IntentContextInterpreter
   * @see com.ibm.wala.dalvik.ipa.callgraph.propagation.cfa.IntentContextSelector
   * @return if check passed TODO: this doesn't check anything yet
   */
  public boolean checkOverridesInPlace() {

    // TODO: Check StartComponentMethodTargetSelector
    // TODO: Check IntentContextInterpreter
    // TODO: Check IntentContextSelector

    return true;
  }

  /**
   * Checks whether stubs are recent enough to contain some used functions.
   *
   * <p>If the stubs are to old some parts that rely on these functions may be skipped entirely.
   *
   * @return if check passed
   */
  public boolean checkStubsVersion() {
    boolean pass = true;

    if (this.cha.lookupClass(AndroidTypes.Fragment) == null) {
      pass = false;
    }

    if (this.cha.lookupClass(AndroidTypes.UserHandle) == null) {
      pass = false;
    }

    if (this.cha.resolveMethod(
            this.cha.lookupClass(AndroidTypes.Activity),
            Selector.make("getLoaderManager()Landroid/app/LoaderManager;"))
        == null) {
      pass = false;
    }

    if (this.cha.resolveMethod(
            this.cha.lookupClass(AndroidTypes.Activity),
            Selector.make("getSystemService(Ljava/lang/String;)Ljava/lang/Object;"))
        == null) {
      pass = false;
    }

    if (this.cha.resolveMethod(
            this.cha.lookupClass(AndroidTypes.Context),
            Selector.make("getSystemService(Ljava/lang/String;)Ljava/lang/Object;"))
        == null) {
      pass = false;
    }

    return pass;
  }

  /**
   * Is enough info present to resolve Intents.
   *
   * <p>This information is needed by the startComponent-functions in order to resolve the target of
   * the call (if enough context is present).
   *
   * <p>If this information is unavailable the call will be resolved to the function
   * AndroidModel.Class.startUNKNOWNComponent which will call all Components of the specific type
   * (Activity, Service, ..) present in the application.
   *
   * @return if check passed
   */
  public boolean checkIntentSpecs() {
    boolean pass = true;

    final List<AndroidEntryPoint> entrypoits = AndroidEntryPointManager.ENTRIES;

    for (AndroidEntryPoint ep : entrypoits) {
      final TypeName test = ep.getMethod().getDeclaringClass().getName();
      if (!this.manager.existsIntentFor(test)) {
        if (test.toString().startsWith("Landroid/")) {
          continue;
        }
        pass = false;
      }
    }

    return pass;
  }

  /**
   * In order to for the startComponent-calls to work components should be set reuse.
   *
   * <p>If components are _not_ set reuse the following will happen:
   *
   * <p>* The caller context can not be set * No result will be transmitted back to onActivityResult
   *
   * @return if the test passed
   */
  public boolean checkAllComponentsReuse() {
    boolean pass = true;

    final IInstantiationBehavior behaviour =
        this.manager.getInstantiationBehavior(
            cha); // XXX: This generates false positives without cha!
    final List<AndroidEntryPoint> entrypoits = AndroidEntryPointManager.ENTRIES;

    for (AndroidEntryPoint ep : entrypoits) {
      final TypeName test = ep.getMethod().getDeclaringClass().getName();
      IInstantiationBehavior.InstanceBehavior behave =
          behaviour.getBehavior(
              test, /* asParameterTo= */ null, /* inCall= */ null, /* withName= */ null);
      if (behave != IInstantiationBehavior.InstanceBehavior.REUSE) {
        pass = false;
      }
    }

    return pass;
  }

  /** Check if an Entrypoint takes an object. */
  public boolean checkNoObjectInEntryPoints() {
    boolean pass = true;

    final List<AndroidEntryPoint> entrypoits = AndroidEntryPointManager.ENTRIES;
    for (AndroidEntryPoint ep : entrypoits) {
      final TypeName[] params = ep.getMethod().getDescriptor().getParameters();
      if (params == null) continue;
      for (final TypeName type : params) {
        if (type.equals(
            TypeReference.JavaLangObject.getName())) { // Why if JavaLangObjectName private? .. narf
          pass = false;
          break;
        }
      }
    }
    return pass;
  }
}
